Many commercial and chemical processes involve mass transfer or heat exchange, and utilize packed columns or chambers to carry out process steps. Such processes can include distillation, absorption and desorption, gas cleaning and drying, scrubbing and various biological processes, such as filtration. Two fluids, usually a gas and a liquid, although two liquids may be utilized, are intermingled within a chamber, typically as counterflow streams wherein two fluids move generally in opposite directions along the same flow axis. The two fluids may however move in the same direction along a flow axis (in a co-current system) or in separate, intersecting directions (in a cross-current system).
Mass transfer and/or reaction rates in such processes increase with increasing amounts of effective surface area that can be wetted by liquid within the chamber and over which the two fluids can then interface with each other. Packing elements are placed in the chamber to increase the surface area available for such interfacing. Packing systems come in two basic types: structured and random. Structured packing systems generally include extended arrays of structured packing elements that are arranged within the chamber. Random packing systems utilize large numbers of individual packing elements which are dumped into the chamber, thereby forming a random array.
Several considerations influence the design of random packing elements. It is important to maximize mass transfer and/or reaction rates through the packing system. A method of maximizing mass transfer and/or reaction rates is to maximize the surface area that can be wetted by a liquid within the chamber, thereby maximizing the area over which two or more fluids may interface. It is important to minimize pressure drop through a packing system. A method of minimizing pressure drop is to maximize the amount of free volume within the chamber by minimizing the volume of random packing element material within the chamber. It is important that the random packing elements be sufficiently strong and rigid to maintain their shape while supporting the weight of other random packing elements located higher in the chamber. It is also important that these random packing elements be capable of low-cost mass production. Indeed, one great advantage of random packing systems over higher-efficiency (high mass transfer and/or reaction rates per unit of pressure drop across the system) structured packing systems is the relatively low cost of random packing systems.
Myriad examples of random packing elements configurations have been utilized in random packing systems. However, a strong need is still felt for random packing elements which, when utilized, can more closely approach the high efficiency of structured packing columns while maintaining the cost advantages of random packing systems. The present invention provides improvements to existing random packing elements which address these needs.